Tightness of joints is an important indicator of the quality of a plumber or gasman. It is necessary to correctly wind the FUM tape: not to allow distortions, to observe the direction of winding, not to be mistaken with the amount of tape. Errors in this matter are fraught with problems with the connection: it either starts to leak, because the fitting will crack when tightened. We will figure out how to properly seal the FUM thread with tape and what is required for this.
What is fum tape?
The abbreviation "FUM" is formed from the name of the material (fluoroplastic, that is, polytetrafluoroethylene polymer) and its purpose (sealing material). The abbreviation fully describes a tool for sealing joints. This is a strip of white (sometimes beige) polymer film. By winding it onto the thread, they prevent leakage of moisture or gas penetration through the connection.
FUM tape appeared as a replacement for sealing materials used previously: tow, linen cords, bandages soaked with paint and other materials on a natural basis. To assess the feasibility of using a new type of sealant, you need to have a good idea of the strengths and weaknesses of the fluoroplastic polymer.
Advantages and disadvantages of the material
The main advantage of the tape, which was immediately appreciated by plumbers and gas workers, is simplicity and ease of use. It does not need to be coated with water-repellent pastes, paint or other substances, so the time to create each compound is reduced. In addition, you do not have to get your hands dirty.
Other benefits of this seal include:
- Resistance to aggressive substances. Even solutions of chemically active substances flowing through pipes sealed with a fluoroplastic sealant will not destroy the packing.
- Resistance to low and high temperatures. The fluoroplastic polymer does not lose elasticity at temperatures from -50 ° C to +210 ° C.
- Unsuitable for the development of microorganisms. Mold does not grow on the surface of the film, nor is this material damaged by bacteria.
The tape can be used to seal threaded joints on pipelines of plastic, metal or metal-plastic elements.
There are some disadvantages. First of all, the tape is not applicable for pipelines with a large diameter (from 50 mm and more). On massive threads, a 0.1–0.2 mm film layer will not provide impermeability to water. In addition, joints sealed with this seal are not recommended to be rotated. Otherwise, the thread with a sharp edge will cut through the material, opening the way for water.
Varieties of tape: choose the right
The first secret that you need to know in order to use the fluoroplastic sealant correctly: there are three types of tape. Each of them is designed for special types of pipelines. Here is a brief description of them:
- To achieve tightness of the threaded connection of pipes in which aggressive liquids will flow, FUM-1 film is used. It is coated with a special lubricant that improves the quality of the seal and makes assembly easier.
- For systems through which oxidizing agents arrive, FUM-2 material is intended. It contains no grease.
- If there are no oxidizing agents, alkalis and other aggressive substances in the environment, a FUM-3 film is suitable. It is also available without lubrication.
No less important than the type of material is the width of the strip. It must strictly correspond to the width of the thread. Therefore, all three varieties are available in several different sizes.
If the type of film or the size of the strip is not selected correctly, it will be very difficult to make the thread impermeable.
Joint Sealing Technology
Another condition for obtaining a good result is compliance with the technology of sealing joints.
The work is performed in the following order:
- Cleaning threads from dirt and oxides. The metal thread is cleaned with a wire brush. The final step is to wipe the parts with rags dipped in a solvent to remove the grease film.
- Selection of film by type and width. The edges should not extend beyond the boundaries of the thread. A too narrow variety is also not suitable: when winding in the place of overlap, the layer will be thicker, and thinner at the edges.
- Winding tape. The turns are done strictly clockwise, with sufficient tension so that the material fits tightly on the thread, but does not cut through.
The tape cannot be rewound. If the winding does not lie correctly during winding, you will have to remove the entire material and rewind.
To work with FUM tape correctly, some skill is required. If you have never used this material before, be sure to practice before assembling the joint (do a few test windings). The expended effort will pay off - you can create neat joints that are not permeable to water, spending a minimum of effort.